#include<bits/stdc++.h>
using namespace std;
int main()
{
	int num=702;
	for(char x1='a';x1<='z';++x1)
	{
		for(char x2='a';x2<='z';++x2)
		{
			for(char x3='a';x3<='z';++x3)
			{
				num++;
				if(num==2019)
				{
					cout<<x1<<x2<<x3<<endl;
					break;
				}	
			}
		}
	 } 
	return 0;
}
